An apparatus for mounting an electronic component (chip) picks up a chip stacked in a part-feeder with a nozzle of a carriage head by vacuum chucking, and then transfers the chip to a specified coordinate spot on a substrate. Since the chip vacuum chucked at the bottom of the nozzle is deviated in position with regard to X, Y and .theta. directions, the deviations are detected by a recognition member and are compensated for before the chip is mounted on the substrate.
The recognition member using a line-sensor is widely known. Typically, the line-sensor comprises photo sensing devices such as CCD (Charge Coupled Device) arranged in linear lines, and the chip is transferred across the longitudinal direction of an array of the sensing devices at right angles. During the transfer, the line-sensor photo-senses the chip to produce surface information of the chip image. The position deviations are detected accurately because CCD is a high resolution device.
A recognition method utilizing a conventional line-sensor is explained with reference to FIG. 13.
FIG. 13 is a top view depicting a chip recognition method by a conventional mounting apparatus of electronic components, where the chip is transferred above a line-sensor 103 incorporated in the mounting apparatus of electronic components. A chip 101 is vacuum chucked at the bottom of the nozzle 102 of the carriage head. The carriage head picks up the chip 101 stacked in the part-feeder by vacuum chucking to the bottom of the nozzle 102, and transfers the chip to the substrate (not shown.) During the transfer, the chip passes above the line-sensor 103, which takes images of the chip 101, and an image recognizing means recognizes the position of chip 101 according to the images, and detects deviations with regard to X, Y and .theta. directions.
The conventional mounting apparatus, however, does not work at a high speed, and a user cannot expect an efficient operation because a single nozzle 102 of a single carriage head picks up one chip 101 at a time, and the nozzle 102 goes back and forth across the line-sensor 103 between the part-feeder and the substrate in order to mount each individual chip onto the substrate.
Further, as shown in FIG. 13, although a transferring direction N1 of the chip 101 must cross the longitudinal direction N2 of the line-sensor 103 at right angles, the angle is sometimes deviated by .theta. with respect to an axis K whose direction is at right angles to N1. (The angle .theta. is described as the "rotation angle" in this specification.) When the line-sensor 103 is slanted as shown, an image of chip 101 taken through the line-sensor 103 is distorted, thereby producing a recognition error. Therefore, the user cannot always expect an accurate mounting of the chip 101 onto the substrate.